Charged particle accelerators used in well-logging generally produce secondary beams of uncharged particles, such as neutrons and photons which effectively penetrate the borehole formation. Such charged particle accelerators are discussed in the background portion of U.S. patent application Ser. No. 7/568,924 and its divisional application. That application also describes an apparatus having a particle source, a voltage supply, and a Cockcroft-Walton voltage multiplier. The voltage multiplier comprises a nested bank of capacitors arranged radially relative to one another to multiply a voltage signal. A linear voltage increase occurs between the capacitors such that voltages of 300 kV are obtainable. The apparatus also includes an accelerator tube that is biased by the multiplied voltage signal.
U.S. Pat. No. 5,124,658 to Adler concerns a Nested High Voltage Generator/Particle Accelerator. The accelerator includes a plurality of high voltage generators nested within one another. Each voltage generator comprises a cup-like housing having a base and a tubular sleeve. A primary transformer winding encircles the nested stack. A secondary transformer winding is between each adjacent pair of housings. A power supply, respective to each of the secondary windings, converts alternating voltage from its respective secondary winding to DC voltage. Specifically, each secondary winding drives a miniature voltage multiplier comprising a capacitor-diode combination which provides the DC voltage for the corresponding generator from an AC input. However, this approach results in difficulties with voltage standoff in the secondary windings and in the voltage multipliers because of the high gradients associated with miniature size.